Write a program to define three variables to hold three testscores. The program should ask the user to enter three test scoresand then assign the values entered to the variables. The programshould display the average of the test scores and the letter gradethat is assigned for the test score average. Use the grading schemein the following table.Test ScoreAverage                 Letter Grade90 orgreater                           A80-89                                      B70-79                                      C60-69                                      DBelow60                                F
Answer: #include<iostream.h>
#include<conio.h>
void main()
{
int a,b,c,avg;
char ch;
cout<<\"\\n enter values of 3 test scores\";
cin>>a>>b>>c;
avg=(a+b+c)/3;
cout<<\"\\n average is \"<<avg;
if(avg<60)
ch=\'F\';
if(avg>=60 && avg<=69)
ch=\'D\';
if(avg>=70 && avg<=79)
ch=\'C\';
if(avg>=80 && avg<=89)
ch=\'B\';
if(avg>=90)
ch=\'A\';
cout<<\"\\n grade is:\"<<ch;
}